MECHANICS AND USEFUL ARTS. 15 



greater display of ingenuity than in the various contrivances for the 

 indication and regulation of time. The following is a mere enumera- 

 tion of some of the more curious products there exhibited : A clock 

 moved by the equilibrium of water and air, very ingeniously con- 

 structed. A clock in a case, which occupied thirty-four years in 

 completing it, with astronomical, chronological, and other movements, 

 wind organ, &c. A geographical clock, showing the difference of mean 

 tune in all the capitals of Europe. A clock showing the days of the 

 month, the months of the year, the motions of the sun and moon, and 

 the state of the tide at some of the principal sea-ports of Great Britain, 

 Ireland, France, America, Spain, Portugal, Holland and Germany, and 

 going for twelve months. A skeleton striking clock, going 400 days, 

 and showing dead seconds by means of a chronometer. A patent tell- 

 tale clock, for the purpose of detecting delinquent servants, and calcu- 

 lated for the express purpose of " regulating " domestics. A clock 

 called the " Perpetual Motion Clock," having no weights or chain, and 

 most curiously made. 



A number of curious watches were also exhibited, one of which 

 goes a year, another showed the time to a sixth of a second, and a third 

 (a second watch) was made of ivory, with gold screws and steel 

 moving powers. It works in ten rubies, and weighed (glass and vaso 

 included) only half an ounce. There were some of the finest speci- 

 mens of miniature watches exhibited that probably have ever been 

 made. These tiny time-keepers were set on card cases, the frames of 

 eye glasses, broaches, rings, &c. Some of them were scarcely the 

 size of the gold dollar, although somewhat thicker. The top of a gold 

 penholder richly set on rubies contained a time-piece with three dials, 

 each one-fourth of an inch in diameter, running a week without wind- 

 ing up, and showing the months, days, weeks, hours and minutes. 



JEWELLERY AND PRECIOUS STONES AT THE GREAT EXHIBITION. 



ONE of the most striking features of the Great Exhibition was the 

 display of a considerable number of gems of rare quality and great 

 value. First in order was the Koh-i-noor, formerly the property of 

 Runjeet Singh, now belonging to the British Crown. Its shape is an 

 irregular oval, 1 inches in length by 1 inch across, weighing nearly 

 280 carats. Two smaller diamonds were placed on either side, one 

 weighing 34 carats, and the other 19 carats. The value of this 

 diamond is estimated at 662,000, but the conventional value of dia- 

 monds is one of the popular errors of the day ; thus the celebrated 

 Napuck diamond, estimated by the East India Company to be worth 

 30,000, realized, when sold in London in 1837, only 7,500. In the 

 Indian collection was exhibited a smaller diamond, the Der-i-noor, 

 which, although insignificant in value compared with the Koh-i-noor, 

 is much more brilliant and effective, from the large surface it exposes. 

 This diamond is set as an armlet, with ten smaller stones around it : 

 together with it were shown a necklace, of 224 large pearls, and a 

 shorter one of 104 smaller pearls ; a necklace of four large rubies, a 

 pair of emerald armlets, a carved emerald and diamond turban orna- 



